The invention is based on an adjustable engine mount as defined hereinafter. An engine mount for supporting a drive motor, for example, on a motor vehicle frame is already known, the damping characteristic of which is variable during operation as well (German Offenlegungsschrift No. 34 41 592). While the support function and the resiliency of this engine mount is attained by means of a rubber element, the hydraulic damping action is turned on and off by subjecting the pressure chamber of the mount to either overpressure or negative pressure from an external air source or vacuum source. The alternation from the damped to undamped operating state and vice versa is performed automatically via an electronic control unit as a function of predetermined parameters.
Given the great number of factors that effect the motions of the engine mounted in the motor vehicle, however, a two-point control of this kind is capable of attaining persuasive suppression of engine vibrations only under certain operating conditions. In all other operating ranges, sacrifices in terms of the comfort of the ride must be expected, as a consequence of vibration of the drive unit that is transmitted to the vehicle frame.